Halftone phase shift photomask and blank for halftone phase shift photomask

Abstract

A blank for halftone phase shift photomask is disclosed. The blank has a transparent substrate, a halftone phase shift layer and a light shielding film, the halftone phase shift layer and the light shielding film being layered in this order on the transparent substrate, and the l light shielding film is a single layered or multiple layered film which has a layer of tantalum.

What is claimed is:  
     
       1. A blank for forming a halftone phase shift photomask which comprises a transparent substrate, a halftone phase shift layer and a substantial light shielding film, said halftone phase shift layer and said substantial light shielding film being layered on the transparent substrate, said substantial light shielding film being a single layered or multiple layered film which comprises a layer containing tantalum as a main ingredient, and said halftone phase shift layer is a single layered or multiple layered film which comprises a layer containing a tantalum silicide as a main component and further containing an element selected from the group consisting of oxygen, nitrogen and fluorine. 
     
     
       2. A blank for a halftone phase shift photomask which comprises a transparent substrate, a halftone phase shift layer and a substantial light shielding film, said halftone phase shift layer and said substantial light shielding film being layered on the transparent substrate, said substantial light shielding film being a single layered or multiple layered film which comprises a layer containing tantalum as a main ingredient and said halftone phase shift layer being a single layered or multiple layered film which comprises a layer containing chromium as a main component and further containing an element selected from the group consisting of oxygen, nitrogen and fluorine. 
     
     
       3. A blank for a halftone phase shift photomask according to  claim 1  or  claim 2 , wherein a halftone phase shift layer is formed on a transparent substrate with having a phase difference φ within the range of nπ±π±3 radian (n is an odd number) according to the following equation:          φ   =         ∑     k   =   1       m   -   1            ×     (     k   ,     k   +   1       )         +       ∑     k   =   2       m   -   1                       2        π        (       u        (   k   )       -   1     )              d        (   k   )       /   λ                                        
       wherein, φ is a phase change caused to light vertically transmitting through the photomask in which a halftone phase shift layer with (m−2) layers is disposed on the transparent substrate, ×(k, k+1) is a phase change occurring in the interface between a k th  layer and a (k+1) th  layer, u(k) and d(k) are the refractive index and film thickness of a material forming the k th  layer, respectively, and λ is the wavelength of exposure light, providing that the layer of k=1 is the transparent substrate and the layer of k=m is air.  
     
     
       4. A blank for a halftone phase shift photomask according to  claim 3 , wherein a halftone phase shift layer is formed on the transparent substrate with having a film thickness which causes the transmittance of exposure light within the range of 1 to 50% when the transmittance of exposure light of the transparent substrate is defined as 100%. 
     
     
       5. A blank for a halftone phase shift photomask according to  claim 1  or  claim 2 , wherein a halftone phase shift layer is formed on the transparent substrate with having a film thickness which causes the transmittance of exposure light within the range of 1 to 50% when the transmittance of exposure light of the transparent substrate is defined as 100%. 
     
     
       6. A halftone phase shift photomask which comprises a transparent substrate, a halftone phase shift layer and a substantial light shielding film, wherein said halftone phase shift layer and said substantial light shielding film being layered on the transparent substrate, said substantial light shielding film being a single layered or multiple layered film which comprises a layer containing tantalum as a main ingredient, and said halftone phase shift layer is a single layered or multiple layered film which comprises a layer containing a tantalum silicide as a main component and further containing an element selected from the group consisting of oxygen, nitrogen and fluorine. 
     
     
       7. A halftone phase shift photomask comprising a transparent substrate, a halftone phase shift layer and a substantial light shielding film, said halftone phase shift layer and said substantial light shielding film being layered on the transparent substrate, said substantial light shielding film being a single layered or multiple layered film which further comprises a layer containing tantalum as a main ingredient and said halftone phase shift layer being a single layered or multiple layered film which comprises a layer containing chromium as a main component and further containing an element selected from the group consisting of oxygen, nitrogen and fluorine. 
     
     
       8. A halftone phase shift photomask according to  claim 6  or  claim 7 , wherein a halftone phase shift layer is formed on a transparent substrate having a phase difference φ within the range of nπ±π±3 radian (n is an odd number) according to the following equation:          φ   =         ∑     k   =   1       m   -   1            ×     (     k   ,     k   +   1       )         +       ∑     k   =   2       m   -   1                       2        π        (       u        (   k   )       -   1     )              d        (   k   )       /   λ                                        
       wherein, φ is a phase change caused to light vertically transmitting through the photomask in which a halftone phase shift layer with (m−2) layers is disposed on the transparent substrate, ×(k, k+1) is a phase change occurring in the interface between the k th  layer and the (k+1) th  layer, u(k) and d(k) are the refractive index and film thickness respectively of a material forming the k th  layer, and λ is the wavelength of the exposure light, providing that the layer of k+1 is the transparent substrate and the layer of k+1 is air.  
     
     
       9. A halftone phase shift photomask according to  claim 8 , wherein a halftone phase shift layer is formed on the transparent substrate with having a film thickness which causes the transmittance of exposure light within the range of 1 to 50% when the transmittance of exposure light of the transparent substrate is defined as 100%. 
     
     
       10. A halftone phase shift photomask according to  claim 6  or  claim 7 , wherein a halftone phase shift layer is formed on the transparent substrate having a film thickness which causes the transmittance of the exposure light within the range of 1 to 50% when the transmittance of exposure light of the transparent substrate is defined as 100%.